(USA TODAY) -- The Centers for Disease Control and Prevention, which has faced congressional hearings and secret government sanctions over its sloppy lab safety practices, is keeping secret large swaths of information about dozens of recent incidents involving some of the world’s most dangerous bacteria and viruses.

CDC scientists apparently lost a box of deadly and highly-regulated influenza specimens and experienced multiple other potential exposures involving viruses and bacteria, according to heavily-redacted laboratory incident reports obtained by USA TODAY. Several reports involve failures of safety equipment. In one, a scientist wearing full-body spacesuit-like gear to protect against lethal, often untreatable viruses like Ebola, had their purified air hose suddenly disconnect – “again” – in one the world’s most advanced biosafety level 4 labs.

After taking nearly two years to release laboratory incident reports requested by USA TODAY under the Freedom of Information Act, the CDC blacked out many details including the types of viruses and bacteria involved in the mishaps and often the entire descriptions of what happened. In several cases, clues about the seriousness of incidents is revealed because CDC staff failed to consistently black out the same words repeated throughout a string of emails.

The CDC would not answer USA TODAY’s questions about specific incidents, which occurred at the agency’s laboratory facilities in Atlanta and Fort Collins, Colo., during 2013 through early 2015.

“None of the incidents described in these documents resulted in reported illness among CDC staff or the public,” the CDC said in a brief emailed statement. Where incidents involved “inventory discrepancies,” the agency said generally the problems were addressed without posing a risk to anybody. The CDC said incident reports cover a time period before the Atlanta-based agency created a new lab safety office in the wake of three high profile incidents during 2014 with anthrax, Ebola and a deadly strain of bird flu.

USA TODAY also revealed details about the operations and safety records of more than 200 high-containment labs across the nation, facilities whose identities have eluded even the Government Accountability Office.

In an effort to determine the extent of the CDC’s lab safety problems, USA TODAY filed a request on Jan. 6, 2015 under the Freedom of Information Act (FOIA) seeking copies of lab incident reports for the previous two years .

But the 503 pages of records the CDC released in many cases look like Swiss cheese when an incident involves any pathogen that is on a federal list of potential bioterror pathogens, called “select agents.” They include pathogens such as those that cause anthrax, Ebola, plague or certain avian or reconstructed flu virus strains.